Through-hole drill depth calculates the total programmed drilling depth needed to fully break through a given material thickness, accounting for the drill point’s breakthrough allowance.
How it works
Programming a through-hole to exactly the material thickness leaves the drill’s conical point still embedded in material at the back face. Full breakthrough requires added depth equal to the point’s length, which depends on drill diameter and point angle; skipping this allowance is a common cause of holes that appear to stop just short of breaking through cleanly.
FAQ
How much extra depth is typically needed? For a standard 118° point drill, the point adds roughly 0.3 times the drill diameter to the programmed depth; sharper 135° points add slightly less, and blunter spot-drill-style points add more.
Related Guides
CNC Calculators · Drill Breakthrough Calculator · Spot Drill Depth Calculator